FDO: Only support locally
The issues:
- The size increase from utilizing FDO is quite large while
utilizing runtime profiles in build.
- By default, FDO is utilized globally if the target arch variant
profiles exist.
- Not all modules can show statistical significance in
performance comparison, yet still suffer the size increase.
The solution:
- Only enable FDO locally with LOCAL_FDO_SUPPORT
for modules which may benefit enough to justify the size
tradeoff.
Solution notes:
- I've noted statistical significance in libwebcore and libskia
thus far from utilizing FDO.
- Analysis included sunspider, drawcanvas benchmarks, as
well as gooda analysis on both arm and x86
- To support runtime profile generation in modules which have
LOCAL_FDO_SUPPORT specified,
BUILD_FDO_INSTRUMENTATION is still used. Otherwise,
if the target arch variant profiles exist, FDO is utilized for
specified modules.
Change-Id: I7e95266943ff47c7d82b02e6200fd09911d0bb57
2 files changed